Question

The average of 10 numbers was found to be 15. Later it was found that one number 36 was wrongly copied as 26. Correct average is
1. 20
2. 18
3. 16
4. 14

Answer 1

Correct Answer - Option 3 : 16

Given:

The average of 10 numbers is 15

one number 36 was wrongly copied = 26

Formula used:

Average = sum of observations/Total number of observations

Calculation:

Average of ten numbers = (sum of 10 numbers)/10

⇒ 15 × 10 = sum of 10 numbers

⇒ 150 = sum of 10 numbers

Later on, one number was written wrong as 26, 

Now,

correct sum of numbers is  = 150 – 26 + 36 

⇒ 160

Correct average = sum of 10 numbers/10

⇒ 160/10

⇒ 16

∴ Correct average is 16